The present invention relates to spinstands for testing a head gimbal assembly.
A so-called spinstand (also known as a head/media test apparatus or head tester) is a mechanical platform that can simulate the environment of a disk drive so that tests can be performed on the various components of a disk drive, such as the read/write head or the disk. Typically a spinstand comprises a high-mass deck on which is mounted a spindle for clamping and rotating a magnetic disk. Also provided on the deck is a mechanism commonly known as a test nest for holding and loading the head to the disk. Test data is then written to or read from the disk with the head.
Testing with a spinstand can be performed in a research and development setting or in a manufacturing setting. For instance, as part of the process of manufacturing most modern disk drive assemblies, the read/write head is subjected to a dynamic electrical test on a spinstand before being incorporated into the disk drive assembly to ensure that the performance of the head is acceptable. Usually the head is tested after having been incorporated into a head gimbal assembly (HGA), such as shown by FIG. 1 and described in more detail below.
In order to test a HGA with a spinstand, the HGA to be tested must be received by the spinstand by attaching the HGA to the test nest. As part of the process of receiving the HGA in a spinstand, electrical connection must be made to the HGA. The head must also be aligned with high accuracy relative to the spinstand, a process commonly known as “precising” the HGA. After testing, the tested HGA is removed from the test nest. These steps can be performed by a human operator. Alternatively, some or all of these steps can be automated.
In handling the HGA during the process of attaching the HGA to the test nest, it is important to do so without causing damage, deformation or marking to the HGA. It is desirable that the attachment process is fast so as to optimise test process speeds. The attachment process must of course grip the HGA firmly during testing. The attachment process should be precise, reliably and repeatable. It is also desirable to keep the apparatus involved in attaching the HGA to the test nest as simple as possible, both to improve reliability and to reduce cost. During test, the HGA must be moved with great precision and preferably with great speed. It is therefore desirable that the attachment parts of the spinstand that hold the HGA during testing allow for precise and fast movement profiles for the HGA. The attachment process should preferably also lend itself to being automated.
Various schemes are known in the prior art for attaching a HGA to a test nest in a spinstand. For example, US2007/0143056 (“Head Gimbal Assembly Loader”), US2005/0056337 (“Method And Apparatus For Head Gimbal Assembly Testing”) and US2007/0136022 (“Alignment Of Unmounted Head Gimbal Assemblies For Testing”) teach a test nest having a collet mechanism for centering and clamping the HGA to the test nest. A separate mechanism called a precising nest is provided away from the test nest for precising the HGA. The precising nest comprises two tapered pins which engage respectively with the boss hole and the tooling hole of the HGA when the HGA is positioned on the precising nest to precise the HGA. A linear motion positioning stage is provided to move the HGAs from the precising nest to the test nest.
US-A-2008/0061776 (“Method And Apparatus For Loading A Read/Write Head To A Spinstand”) discloses a spinstand having separate precising stations that precise a HGA away from the test nest before the HGA is transferred to the test nest by a linear actuator.